Q: I've been in rehab for a back injury. My program is going to be changed next week to "core training." What is it and what does it do?

A: Over the past few years physiotherapists have been looking for ways to treat the muscles in the low back area. There is a theory that the local muscle system is key to the health of your back.

Muscles that help stabilize the spine and hold it steady are called core muscles. These include the transverse abdominal and low back multifidus muscles. The multifidus
muscle is a series of short muscle fibers close to the spine. They are part of the "deep" muscles of the spine.

Recently researchers think they found another "core muscle": the psoas. This muscle goes between the lumbar spine and the femur (thigh bone). It works to flex the hip and sometimes the spine.

Contracting the core muscles controls how much the vertebra slide and twist. The effect is to increase the stiffness of the spine. The result is to protect the back from injury.

Your new exercise program will focus on contracting and holding the core muscles while moving the arms and legs. A variety of positions are used from standing to hands and knees and lying down.

Karen L. Barker, PhD, MCSP, et al. Changes in the Cross-Sectional Area of Multifidus and
Psoas in Patients with Unilateral Back Pain. The Relationship to Pain and Disability. In
Spine. November 15, 2004. Vol. 29. No. 22. Pp. E515-E519.